Computing instrument



comprises a cylindrical element 1 provided Awith bengthat the movement 0f the"slide velement :"05 the relative movementbetween the members 1 'Position With respect t0 theelement 21-7 Patented ,Dec.; 1.9 *y Y t y Y l l UNITEDSTA'res{PATENr0151510;

Application April 21, 1932; seriaLNO. ,606,692 1 claim. (or zas-'67) This invention relates to computing instrurespond to thescales ordinarily marked Ar and ments of the slide-rule type and hasl for its ob- B respectively on straight rules. ject to vprovide an improvedconstruction whererThe helical Aelement 3`is made of sheet mateby, with an instrument of a given length, calcurial and the graduated scales arey placed on the "195, lations can be effected over a greater range and faces of the elements. By constructing the de- 5' With greater aCCulaCy than With an Ordinary vice in this manner agreatly increased number straight `slide-rule. y i v of `,convolutionsv and length of scale per unit of n v According to the present invention the slide.- length "can be obtained. As illustrated, the elevrule comprisesahelical'elementbearing through' ment 2 is 'separate from the support 1 but is id. out its length slide-rule graduations, and a secrigidly mounted thereon.v Forv example, the eleond helical element slidably mounted in the ment 2 may be securely mounted in a helical space between the convolutions of said first mengroove in the support 1. The movable member 3 tioned element and bearing throughout its length may be` rotatably mounted on the support 1 or yslide-rule graduations co-operating with.. the in a helical groove therein, and both members graduations on the first mentioned element, said 2 and` 3 areV preferably arranged with their con. helical elements' beingof fiexiblesheet material volutions` as closely together as possible. and each having a vmultiplicity of convolutions. t The members 2 and 3 are made of iiexible The invention consists in the combination and sheet material such as paper, thin metal, celluarrangement of parts hereinafter described and loid or the like, so that the elements may be ,Y

more particularly pointed out in the appended yeasily separatedwith the operators linger in f claim. order to expose the desired portion of the scales.

Referring now tothe accompanyingv drawing, If desired, one of .the elements may be trans# which illustrates, by Way of example, certain parent. i' A embodiments of the inventiom- Y `For the purpose of easily manipulating the Figure 1 is'an end elevation of one form'of `movable element, the `latter may be made of'sthe invention; slightly'larger diameter than the' elementl 2, as Figure 2 is a side elevation partially in secindicated in Figure 2; or ther elements may be tion on the line 2 2 kof Figure 1; made of the same diameter and a projection 5 Figure 3 is an isometric View of a slightly modf `provided 0h the movable element, aS ShOWIl in ied form of the arrangement shown in Figures Figure 3. t i 1 and 2, the same reference numerals with the The Operation'ef the device will' not be de-y index 'letter a added, being `used to indicate scribed in detailas the cooperation of the scales ycorresponding parts. to effect various calculations is exactly the same According to Figures 1 and 2 the invention as Athat of a straiglflt rule, the only difference a helical element 2. A helical member 3 is, ar- 3 is helical instead of linear.V Y ranged in the narrow space between the convo- Ih Figure 1 the elements are ShOWn in .the lutions of the element 2. J zero position, while in v.Figure `3 the element 3a suitable means are provided for facilitating is shown rotated several turns from the zero and 3. For example, the element 1 may be` pro- To facilitate recognition of the! coils of the 95 vided with a handle 4 of suitable length, dependtwo elements they may be Coloured differently. ing on the length of the member 3, andthe' ele- FOI example, the. element 2a. may be made white Q` ment 3 may bemade of a slightly larger diamand the elementSa of somecontrasting colour, A45 eter than the member 2. The marginal portions 'as indicated by Stippling in Figure 3. i160 ofthe elements 2 and 3 are provided with co- Il? Will he Seen that the improved T1118 0f 21,113/

operating series of graduations. As shown, one given length will contain a scale of very much y series of Vgraduations is provided on the element 4greater length than a Straight rule of the same I 2, as indicated at 6`, and one on the helix 3, as length and that the Scales may be much more *5gl at; 7, Y 1 highly subdivided so as to obtain a `.greater 10'5 No attempt hask been made in the drawing to degree 0f accuracy. o illustrateA the graduations accurately, as these v It will be understoodV that the rdevicemay y.

may take the form of anywell known arrangebe of any convenient diameter and maybe ment of graduations employed on existing Yslideextended to any desired number .of convolutions'. Y

"5'5 rules. For example, the series 6 and 7 may cor- It will also be understood that the foregoing in) ably mounted in the space between the convolutions of said first mentioned element and bearing throughout its length slide-rule graduations cooperating with the graduations on the rst mentioned element, said helical elements being of flexible sheet material and each having a multiplicity of convolutions.

NoBBEnT J. MEQGHER. 

